In recent years, in rotary electric machines that are mounted to vehicles, there is demand for downsizing to accompany size reductions in mounting space for rotary electric machines in vehicle engine rooms, and for improvements in generated power output due to increases in vehicle load. There is also demand for improvements in reliability.
In consideration of such conditions, various proposals have been made in order to achieve compactness and high output, as well as improvements in quality. In the armature winding that is described in Patent Literature 1, for example, windings that are formed so as to have barrel-shaped cross sections are housed multiply in slots into which insulating sheets have been mounted. The windings are covered by insulating coatings, the insulating coatings on the circular arc-shaped surfaces of the barrel-shaped cross sections contact each other, and the insulating coatings on the side surfaces contact the armature core so as to have the insulating sheets interposed. The insulating coatings on the circular arc-shaped surfaces are formed so as to be thicker than the insulating coatings on the side surfaces.